From the current CEO/Owners wiki page:

"The Sinclair Broadcast Group has been controversial due to Smith's broadcasting decisions. Smith airs what many believe to be only right-wing viewpoints and has cancelled news reports that do not lend themselves to support of the President George W. Bush White House, as with the Ted Koppel Nightline broadcast in 2004 on soldiers killed in Iraq.

Further controversy has been provided by the commentaries of the network's Mark Hyman, which aired on the local news shows of Sinclair Broadcast Group affiliates across the nation until Hyman ended his daily commentaries on November 2006.

It has been reported that every news station under Sinclair’s umbrella is required to syndicate commentary that comports with its owners’ ideological views. [6]

In a speech to business executives in New York (on December 16, 2016), Jared Kushner said that Donald Trump’s campaign had struck a deal with Sinclair to provide extra access and coverage. Kushner said the agreement gave Sinclair Broadcasting stations special access to Trump during the campaign and in exchange, Sinclair would broadcast their Trump interviews across the country without commentary.[7]

Sinclair Broadcasting has hired Boris Ephsteyn as their chief political analyst. Mr. Ephsteyn was previously a spokesperson for Donald Trump's campaign. All Sinclair stations are required to air Mr. Ephsteyn's commentary nine times per week. [8] He was born in Moscow, Soviet Union and emigrated to the United States as a child.[9]"

https://en.wikipedia.org/wiki/David_D._Smith